Abstract African American and Latina women, as well as women living in poverty, are at disproportionate risk for contracting HIV (CDC, 2018). Prevalence is increased further in these women if they have other risk factors for HIV, including substance use, history of intimate partner violence, and homelessness. Despite the relatively high prevalence rates in these populations, many women with these characteristics have never been tested for HIV (CDC, 2016a). Knowledge of one?s HIV status is crucial for rapid access to treatment and reducing the spread of HIV. Thus, effective interventions for enhancing testing in these women are an imminent need. Reinforcement interventions can be efficacious in enhancing testing, and our NIH-funded study in Canada (Hull et al., 2013) found that rates of successful testing in high risk adults increased from 11% to 83% when reinforcers were provided. In the proposed project, we will evaluate a systems approach applying a similar intervention for enhancing HIV testing in high risk women. We will train ~50 staff from multiple community agencies that provide services to high risk women to encourage HIV testing and deliver reinforcement for testing. After staff training, 334 women recruited at these community agencies will be randomized to standard care referral procedures plus HIV risk reduction education or the same plus reinforcement, in which they can receive up to $40 for completing HIV testing at study initiation and for repeat testing 6 and 12 months later. Primary systems outcomes will include staff knowledge and attitudes about HIV testing and reinforcement interventions. The primary client outcome will be proportions who undergo testing. Exploratory analyses will evaluate moderators of testing, including clinic, clinician, and client characteristics, as well as indices of change in sexual risk and other behaviors over time and by condition over time. We will also estimate costs of the intervention and its cost effectiveness in promoting HIV testing. This project evaluates new models to promote HIV testing. It institutes trainings and provides direct resources for integrating reinforcement-based HIV testing referral procedures to women accessing services at substance abuse treatment clinics, Federally Qualified Heath Centers, domestic violence agencies, and homeless shelters. Trainings address systemic and structural issues and provide concrete methods and resources to enhance testing (i.e., reinforcers). Our experiences integrating reinforcement for substance use treatment through the Veterans Administration (VA) speak directly to this project?s potential success, with over 90% of VA clinics implementing reinforcers after training (DePhillipis et al., in press; Petry et al., 2014a). Due to this success, the VA has committed to supporting this intervention indefinitely. This project likewise proposes to initially provide reinforcers with the presumption that, if effective, costs will be justified by HIV testing outcomes. Thus, results from this project hold the potential to establish a highly effective method to increase HIV testing in vulnerable women, which could be readily applied more globally to slow the spread of HIV.